/*

 * Licensed to the Apache Software Foundation (ASF) under one

 * or more contributor license agreements.  See the NOTICE file

 * distributed with this work for additional information

 * regarding copyright ownership.  The ASF licenses this file

 * to you under the Apache License, Version 2.0 (the

 * "License"); you may not use this file except in compliance

 * with the License.  You may obtain a copy of the License at

 *

 *     http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

package com.bff.gaia.unified.sdk.util;



import com.bff.gaia.unified.sdk.options.PipelineOptions;

import com.bff.gaia.unified.sdk.state.StateContext;

import com.bff.gaia.unified.sdk.transforms.CombineWithContext.Context;

import com.bff.gaia.unified.sdk.values.PCollectionView;



/** Factory that produces {@code Combine.Context} based on different inputs. */

public class CombineContextFactory {



  private static final Context NULL_CONTEXT =

      new Context() {

        @Override

        public PipelineOptions getPipelineOptions() {

          throw new IllegalArgumentException("cannot call getPipelineOptions() in a null context");

        }



        @Override

        public <T> T sideInput(PCollectionView<T> view) {

          throw new IllegalArgumentException("cannot call sideInput() in a null context");

        }

      };



  /** Returns a fake {@code Combine.Context} for tests. */

  public static Context nullContext() {

    return NULL_CONTEXT;

  }



  /** Returns a {@code Combine.Context} that wraps a {@link StateContext}. */

  public static Context createFromStateContext(final StateContext<?> c) {

    return new Context() {

      @Override

      public PipelineOptions getPipelineOptions() {

        return c.getPipelineOptions();

      }



      @Override

      public <T> T sideInput(PCollectionView<T> view) {

        return c.sideInput(view);

      }

    };

  }

}